Safety procedure for optical fiber systems and safety interface to carry out such safety procedure

Abstract

The invention refers to a safety procedure for optical fiber systems. Such systems are widely used in telecommunication to transport optical signals between a transmitter terminal and a receiver terminal. By the invented safety procedure the optical input power fed into said optical fiber system is automatically shut off or at least reduced in case of an unintended escape of light from at least one fiber. A safety interface, provided in the transmission line detects changes of the total optical output power in at least one fiber and initiates a shut-down of the input power as soon as a decrease of the total output power is detected, that exceeds a predefined value within a predefined time window. Thus the slope of the total output power is measured and evaluated rather than its absolute value.

1. A safety procedure for optical fiber systems, transporting optical signals between a transmitter terminal and a receiver terminal, with at least one pump source to enhance said optical signal, by which safety procedure the optical input power fed into said optical fiber system is automatically shut off or at least reduced in case of an unintended escape of light from at least one fiber, wherein
 a safety interface is provided in the transmission line, said interface detecting changes of the total optical output power in at least one fiber to be received by said receiver terminal and initiating a shut-down of said input power as soon as a decrease of said total output power exceeding a predefined amount is detected within a predefined time window, wherein said predefined time window is about 1 ms. 
 
   
   
     2. Safety interface according to  claim 1 , wherein said predefined value is a value above a no signal value. 
   
   
     3. Safety procedure according to  claim 1 , wherein the optical fiber system is an unrepeated system with high energy pump sources. 
   
   
     4. Safety procedure according to  claim 1 , wherein in case of a safety shut-down all pump sources are shut down. 
   
   
     5. Safety procedure according to  claim 1 , wherein in case of a safety shut-down only the pump sources of those fiber are shut down, in which a failure has been detected. 
   
   
     6. Safety procedure according to  claim 1 , wherein in case of a safety shut-down also signal sources are shut down. 
   
   
     7. Safety procedure according to  claim 1 , wherein closed to or in the transmitter terminal a safety interface is provided, said interface detecting a portion of pump power per fiber, that reaches the transmitter terminal, and initiating a shut-down of the signal power as soon as a decrease of pump power exceeding a predefined value is detected. 
   
   
     8. Safety procedure according to  claim 1 , wherein at least one piece fiber amplifier is inserted in the fiber line. 
   
   
     9. Safety procedure according to  claim 1 , wherein more than one time window are predefined and the safety shut-down occurs a soon as a detected decrease of total output power exceeds the predefined value within any of said time windows.